大蹼铃蟾的两性异形

2018年6—8月,测量采自云南省昆明市金殿水库后山的71只(47♂,24♀)大蹼铃蟾Bombina maxima成体的体长、头长、头宽等15项形态特征指标并检验该物种的两性异形。结果表明:雄性平均体长为53.54 mm±1.14 mm,雌性平均体长为52.74 mm±1.45 mm,雄性与雌性平均体长比为1.015,两性异性指数为0.01;大蹼铃蟾的体长、体质量与性别之间的差异无统计学意义;除了雌性的眼间距外,其余13项形态特征与体长均有极显著相关性;以体长为协变量的协方差分析结果显示,大蹼铃蟾的头长、吻长、前臂宽、腿或后肢全长、胫长、胫宽和跗足长在两性间的差异有高度统计学意义;雄性的这7项形态特征随体长的生长速率大于雌性。性选择假说能解释大蹼铃蟾的两性异形现象。     

Tuberculate micro-ornament on the juvenile shell of Middle Jurassic ammonoids

In two genera of Callovian Ammonitina of distinct superfamilies, the juvenile shell displays a tuberculate micro-ornament in addition to growth lines. In contrast to the circular micro-tubercles of the ammonitella shell, post-embryonic tubercles are oval to longish in outline. They are arranged in rows running parallel to the growth lines in Kosmoceras (Spinikosmoceras) and cross the growth lines in Binatisphinctes.     

Dimorphism of Spermatozoa in the Sea Urchin Strongylocentrotus nudus

A phenomenon of dimorphism in spermatozoa has been revealed for the sea urchin Strongylocentrotus nudus. The spermatozoa are different in the configuration of the circular mitochondrion. The bulk of male gametes (73.4%) have a symmetrical mitochondrion, whereas the remainder spermatozoa (26.6%) have an asymmetrical one. No other ultrastructural differences in the structure of spermatozoa have been revealed. The two types of spermatozoa are supposed to represent different kinds of normal gametes capable of fertilization.     

奇台沙蜥生长过程中的两性异形

研究奇台沙蜥Phrynocephalus grumgrzimailoi头、尾、腋胯距大小在个体发育过程中的变化.成体体长(SVL)无显著的两性差异,两性异形主要表现为雄性个体有较大的头部(头长和头宽)和尾部,雌性具有较大的腋胯距.头、尾、腋胯距大小的两性异形在幼体就已存在,并随个体发育的进行变得更加显著.不同年龄组两性个体头部、尾部、腋胯距随SVL呈异速增长,表现为两性头部的增长速率在个体发育过程中逐渐增大,尾部的增长速率逐渐减慢,腋胯距在雌性蜥蜴中增长速率逐渐增大,在雄性中逐渐变小.     

Patterns of biotic change in Middle Jurassic to Early Cretaceous Tethyan radiolaria

The rate of taxic turnover of nearly 400 radiolarian species/subspecies is analyzed in order to document long term biotic change of plankton during the Middle Jurassic to Early Cretaceous (Aalenian to Aptian). The pattern and dynamic of diversity change is described using four indices: rate of species first and last occurrence, rate of diversification and rate of turnover. Plots of cumulative sampling effort suggest that the analyzed data represent an adequate sample of total standing diversity for most examined stages. Rates of species first occurrence exceed rates of last occurrence for most of the Middle Jurassic, except for the middle Bajocian. In contrast, the Late Jurassic was a time of decreasing radiolarian diversity and the Kimmeridgian records the lowest rate of diversification. It is followed by a dramatic increase in first occurrences near the Jurassic–Cretaceous boundary with as a result the highest rate of diversification recorded in the late Tithonian. Regional radiolarian diversity was stable throughout most of the Early Cretaceous. A stratigraphic permutation test was performed to assess the influence of uneven sampling on the observed pattern of taxic turnover and identified the intervals for which randomly obtained patterns are significantly different from the observed pattern. The Kimmeridgian and late Tithonian events coincide with substantial climate-derived perturbations in water cycling, nutrient supply and oceanic productivity. They point to a negative relationship between radiolarian macroevolution and changes in the state of nutrient availability, although further work is needed to refine the temporal resolution of this relationship and to explore ecological aspects of its causal link with respect to radiolarian evolution.     

Developmental Aspects of Sexual Dimorphism in Hominoid Canines

We examined the histology of canine teeth in extant hominoids and provided a comparative database on several aspects of canine development. The resultant data augment the known pattern of differences in aspects of tooth crown formation among great apes and more importantly, enable us to determine the underlying developmental mechanisms responsible for canine dimorphism in them. We sectioned and analyzed a large sample (n = 108) of reliably-sexed great ape mandibular canines according to standard histological techniques. Using information from long- and short-period incremental markings in teeth, we recorded measurements of daily secretion rates, periodicity and linear enamel thickness for specimens of Pan troglodytes, Gorilla gorilla, Pongo pygmaeus and Homo sapiens. Modal values of periodicities in males and females, respectively, are: Pan 7/7; Gorilla 9/10; Pongo 10/10; and Homo 8/8. Secretion rates increase from the inner to the outer region of the enamel cap and decrease from the cuspal towards the cervical margin of the canine crown in all great ape species. Female hominoids tend to possess significantly thicker enamel than their male counterparts, which is almost certainly related to the presence of faster daily secretion rates near the enamel-dentine junction, especially in Gorilla and Pongo. Taken together, these results indicate that sexual differences in canine development are most apparent in the earlier stages of canine crown formation, while interspecific differences are most apparent in the outer crown region. When combined with results on the rate and duration of canine crown formation, the results provide essential background work for larger projects aimed at understanding the developmental basis of canine dimorphism in extant and extinct large-bodied hominoids and eventually in early hominins.     

东方蝾螈性二型性特征分析

以东方蝾螈大别山种群为实验材料,随机选取162只蝾螈(雄52只,雌110只),通过单变量、双变量、多变量分析的方法,进行11项体征的测量分析.结果表明,头体长是本研究的最适单变量,且头体长与腋胯距之间的相关性最高;PCl在雄性和雌性中均与头体长密切相关,且大多数体征与头体长进行比例分析均显示出异速生长关系,东方蝾螈性二型性普遍存在.本研究中11项体征呈现符合Renseh法则的雌性依赖性二型性演化特征,这种性二型性特征可能是一系列复杂的非对称性选择的结果.     

The genus Kepplerites Neumary et Uhlig (Kosmoceratidae,Ammonoidea) in the Bathonian-Callovian beds (Middle Jurassic) of the Russian Platform

The succession of early species of the genus Kepplerites is established in the Upper Bathonian-Lower Callovian beds of Central Russia and compared with the ammonoid succession of East Greenland and Western Europe. Late Bathonian members of the genus Kepplerites from the Middle Volga Region are generally similar, though not identical to those from Greenland, whereas the Early Callovian Kepplerites species and their immediate Bathonian ancestors are represented by species common to all three regions. The analysis of the ammonoid distribution suggests a connection between the East Greenland and Central Russian marine basins in the Early and Middle Bathonian and in the Early Callovian, and their short-term isolation in the Late Bathonian. A new species, Kepplerites (Kepplerites) aigii sp. nov., is described from the Upper Bathonian (keuppi Zone) of the Alatyr River basin (Middle Volga Region).     

皖南花猪11种血液生化指标的发育性变化及性别差异

随机选择出生30、45、90、180日龄的皖南花猪公母各5头,测定了11项血清生化指标.结果显示:血糖(GLU)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、游离脂肪酸(FFA)、脂联素(ADP)、瘦素(leptin)和IgG有极显著的发育性变化(P0.01);而甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、IgA和IgM等没有明显的发育性变化.母猪的TG、TC、HDL-C和IgM极显著或显著大于公猪(P0.01或P0.05),其他血清生化指标虽在总体上没有性别差异,但在有些日龄差异明显,大多表现为母猪在90或180日龄大于公猪.结果表明:皖南花猪血液生化指标有特定的发育性模式,并存在不同程度的性别差异.     

Sexual Dimorphism in the Response of the GABAergic System to Estrogen Administration

Abstract: Administration of estradiol benzoate to gonadectomized female rats results in up-regulation of CNS γ-aminobutyric acid (GABA) receptors. The increase of [³H]muscimol binding activity is observed in six of the seven brain areas examined. The same treatment, performed in castrated male or and rogenized female rats, induced an increase of [³H]muscimol binding only in the striatum. Evidence is provided suggesting that the dimorphic sensitivity of GABA receptor is not correlated with the difference in spontaneous motor activity reported between male and female rats.     

Jurassic radiolarites in a Tethyan continental margin (Subbetic, southern Spain): palaeobathymetric and biostratigraphic considerations

A region of the pelagic Subbetic basin within the Southern Iberian Continental Margin is studied in lithostratigraphical and biostratigraphical detail. Jurassic radiolarites (Jarropa Radiolarite Formation, Bathonian–Oxfordian) interbedded with shallow-water marine limestones have been recognized. Underlying the radiolarites (Camarena Formation, Bajocian) are oolitic limestones showing shallowing-upward cycles with karstic surfaces on the top, corresponding to deposition on an isolated carbonate platform on volcanic edifices. The Milanos Formation (upper Kimmeridgian–Tithonian), overlying the radiolarites, contains calciclastic strata with hummocky cross-stratification, which indicate outer carbonate ramp deposition. In the Jarropa Radiolarite Formation some calcisiltite strata with hummocky cross-stratification have been found. The bathymetry of the Subbetic Jurassic pelagic sediments, including the radiolarites, is considered as moderate or shallow in depth. We suggest that the pelagic character of the Jurassic sediments in this margin and their equivalents in other Alpine domains is a consequence of distance from the continent (beyond the pericontinental platform) but not necessarily of depositional depth.     

Ammonite eggs and ammonitellae from the Kimmeridge Clay Formation (Upper Jurassic) of Dorset, England

Eight clusters of small spherical and subspherical objects, some isolated and some associated with shells of perisphinctid ammonites, have been recovered from the Lower and Upper Kimmeridge Clay (Upper Jurassic) of the Dorset coast, England. They have been interpreted as ammonite egg sacs and represent the freshest and best-preserved examples known so far. Their structures and the ecological framework in which they occur are discussed. The parents are thought to be members of the two eudemic genera Aulacostephanus and Pectinatites that dominate the biostratigraphy of the ammonites in the range of the Kimmeridge Clay in which they occur. Isolated nuclei of ammonitellae have also been recovered.     

Dimorphism of Benjaminiella poitrasii: Isolation and biochemical studies of morphological mutants

The yeast-mycelium dimorphims of the genus Benjaminiella poitrasii has been investigated. To understand the mechanism of dimorphism two stable yeast-phase mutants (Y-1 & Y-2) and one slow growing mycelial mutant (M-1) of B. poitrasii were isolated after NTG treatment of parent strain spores and studied for their biochemical characteristics. Effects of (i) kind and concentration of carbon source, (ii) presence of complex organic nitrogen and (iii) C:N ratio in the growth medium on the morphology of parent and mutant strains were carried out at 28°C under shaking conditions. Ethanol induced morphological change and its reversal were studied in all the strains in order to elucidate the possible mechanism of morphogenesis.     

An early Bathonian Tethyan ammonite fauna from Argentina

Evidence for the Lower Bathonian Substage in most of the Pacific area has been lacking or controversial because index ammonoids of the Tethyan Subrealm in southern Europe and North Africa were unknown. During the Bathonian, the East Pacific margin belonged to either the Boreal Realm or the East-Pacific Subrealm of the Tethyan Realm, each with faunas distinctly different from the Eurafrican Tethyan faunas that form the basis for the chronostratigraphical standard. The first representatives of Morphoceras from South America, M. gulisanoi sp. nov., here described from a single locality in southern Mendoza Province, clearly document the Lower Bathonian Substage, probably the Zigzag Zone. Associated ammonoids are the perisphinctoidean Procerites cf. schloenbachi de Grossouvre and the oppeliid Oxycerites ( O. ) cf. aspidoides (Oppel), also typical Tethyan elements but less useful for dating.     

Sexual Dimorphism in the Hindlimb Muscles of the Asiatic Toad(Bufo gargarizans)in Relation to Male Reproductive Success

In many anurans, the forelimb muscles of males are used to grasp females and are often heavier than those of females despite the larger female body size. Such sexual dimorphism in forelimb musculature is thought to result from sexual selection. In addition, the hindlimbs of frogs and toads play an important role in the reproductive process as amplectant males can expel rivals with robust hindlimbs through kicking. In this study, the sexual dimorphism in dry mass for six hindlimb muscles of the Asiatic toad(Bufo gargarizans) was investigated. The results showed that, when controlled for body size, the hindlimb muscle mass of males significantly exceeded that of females for every muscle. The hindlimb muscle mass of amplectant males was also significantly larger than that of non-amplectant males. These results suggested that if strong hindlimb muscles could improve mating success of males, sexual selection would promote the evolution of dimorphism in this character.